(19)
(11) EP 1 895 736 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.05.2008 Bulletin 2008/21

(43) Date of publication A2:
05.03.2008 Bulletin 2008/10

(21) Application number: 07115285.4

(22) Date of filing: 30.08.2007
(51) International Patent Classification (IPC): 
H04L 27/36(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR
Designated Extension States:
AL BA HR MK RS

(30) Priority: 30.08.2006 SE 0601794

(71) Applicant: Nera networks
5020 Bergen (NO)

(72) Inventors:
  • Lund, Sigurd Andre
    NO-5259, Hjellestad (NO)
  • Vahlin, Anders
    NO-5222, Nesttun (NO)

(74) Representative: Bergquist, Kjell Gunnar 
Albihns Göteborg AB Box 142
401 22 Göteborg
401 22 Göteborg (SE)

   


(54) A method and a device for the detection and estimation of quadrature defects


(57) A method for use in a circuit (100) which uses I and Q signals in a quadrature modulator (150), and is intended to correct quadrature defects between the I and Q signals. The method comprises sampling the first and second signals I and Q before they are input to the quadrature modulator (150), evaluating (130) where in an I and Q coordinate system the I and Q samples are positioned, and comparing (170,180) the level of the output of the quadrature modulator (150) to a threshold. If the level exceeds the threshold, the point defined by the I and Q samples is evaluated for use as input to a counter (131-134). The output of the counter (131-134) is used as input to a control loop (160) for evaluating and correcting a quadrature defect, the magnitude of the defect being given by the value output by the counter (131-134).







Search report